Growth on new construction trusses

I’m curious how much y’all would sound the alarm on this if you came across it. Many of the trusses in this attic had signs of some growth. Theoretically, if all else is done properly, it will dry out and it won’t continue to grow, right? On the other hand, this is brand new construction and I sure wouldn’t want my attic to look like this if I was the buyer. I obviously called it out but don’t want to be an alarmist if not necessary.

I need to go ahead and take the mold course to get a better grasp on when/when not to be concerned and also types of remediation for my own knowledge. What would be the process to fix this? Just a surface cleaning? Does it completely wipe off or how does one know when its clean? Thanks in advance for the advice. Mold/growth is definitely one of my weak points and i’d like to be able to better discuss it with clients.

Maybe the trusses were left outside and not properly covered for an extended period of time during the build.

As long as the ventilation in the attic is ok it shouldn’t get any worse, but I wouldn’t worry about specifying whether it’s a major or minor problem, just that there is mold like substance present on attic truss framing.


I’m not a mold expert, BUT, as Brian noted, lumber that sits outdoors in damp/wet conditions or in direct contact with soil will discolor like that. When I see wood in this condition I scratch, poke, and wipe it off to see how deep into the wood fibers it goes.
In pic #3 only one small board has discoloration. Everything around it is clean. I would think the “microbial growth” occurred prior to construction based on what I see in the pictures and should be fine IF moisture levels in the attic remain low, however if a roof leak were to happen, it could be kindling for the fire so to speak.
I would note in my report that “possible microbial growth was observed and it should be tested by a qualified specialist” and leave it at that. Let the mold tester be the alarmist about remediation if the client wants to hire one…


Thanks, I appreciate both of your responses! I agree, based it only being found on the trusses, pre-construction definitely makes sense, I was just unsure of what that would lead to over time.

1 Like

Go wast your time on something else. Like the bathroom. There is mold in there even if you can’t see it. And it’s indoors not the outdoor attic.

David, I’m still taking classes and trying to learn as much as I can. Does your response imply that documenting mold in an attic space is a “waste of time”? What would you do in this situation (finding mold on attic trusses)?

From the things I learned so far, documenting mold seems pretty important…

1 Like

Never Document “Mold” unless it has been tested and only use the test result (paper work) as the documentation. I would also be very careful about even using “that word” in a report unless it has been tested and identified as such. But by all means reporting of what appears to be a “biological growth” is important.


Larry has some great advice and you are on the right track to learning.


You asked if this “looked” like a mold issue. My statement is based upon what you showed us.

As for whether it’s important not, if it’s not inside the house (and the attic is not) I don’t consider it an issue until it starts growing mushrooms.

It takes a constant particular environment (based upon the type of fungus) for fungus to try and exist uninterrupted. If you see mold and you see conditions that perpetuate a mold issue like elevated moisture, lack of ventilation, deterioration of the materials of this on, these are the conditions that are actually worse in must be addressed in the existence of mold because if these are not repaired it would just recur. Thus my statement about looking in the bathroom because that is where there is moisture warm perpetual conditions because of what that room is used for.

Some people indicated that this could be from exposure during the construction phase. That would be a good assumption in this case.

You also must consider the type of mold. Some are health issues but most are damaging organisms to the structure.

If you’re just trying to sell an additional service then none of this matters.

Mold is like rust. You can clean it off, but that doesn’t kill it, it will just come back. Mold has roots that usually grow deep into the fibers of the wood or other organic material that it is feeding on. And like rust, you can clean it off the surface, but it will remain inactive, for years, until it gets a source of moisture and then it will activate and “regrow”.

Never say you saw a mold-like substance or something that appears dead. As Larry and others have said, call it something other than mold, like a “biological growth” that you might want to recommend for further testing. It’s a slippery slope, and many inspectors have gotten into trouble for not identifying a biological growth cause they thought it was dead, only to have it start growing again when the client (who has severe mold allergies) moved in and now wants to know why you didn’t identify it during your inspection cause they now consider the house uninhabitable for them.

1 Like